Electron emission control tube



March 22, 1966 J, MacGRlFF 3,242,261

ELECTRON EMISSION CONTROL TUBE Filed April 22, 1960 4 Sheets-Sheet l fl/KW A Tran/v5 March 22, 1966 J. E. MacGRlFF 3,242,261

ELECTRON EMISSION CONTROL TUBE Filed April 22, 1960 4 Sheets-Sheet z I||llllllllllllllllflllllll- 8 I4 I 1 H I 2 IN V EN TOR. Jim 6. Mar 6k/FF ArTaeA EY March 22, 1966 J. E. MacGRlFF 3,242,261

ELECTRON EMISSION CONTROL TUBE Filed April 22, 1960 4 Sheets-Sheet 5 IN V EN TOR. $9M E. MA: GIWFF March 22, 1966 .1. E. M GRlFF 3,242,251

ELECTRON EMISSION CONTROL TUBE Filed April 22, 1960 4 Sheets-Sheet G Tia. I4

15 5 6A/4 Tig- 65 W IIIIJIIIHIIHHHIHIIHIIHH llllllllllllllllilllllllllllllll! United States Patent 3,242,261 ELECTRON EMISSION CONTROL TUBE Jack E. MacGriff, 17205 Lahser Road, Detroit, Mich. Filed Apr. 22, 1960, Ser. No. 24,168 13 Claims. (Cl. 178-6.6)

The present invention relates to an Electron Emission Control Tube and Method of Printing, and is a continuation-in-part of my application Serial No. 607,446, filed August 31, 1956, now Patent No. 2,934,673, dated April 26, 1960, and application Serial No. 623,152, filed November 19, 1956, now abandoned.

The difficulty with image control tubes such as Kernkamp 2,291,476 and others, is that they are mechanically impossible to construct with close spacing of the end-face conductors; they are not designed for electron emission from the ends of the target conductors across a space; the trace of the electron beam is not visible during operation, and focussing and alignment of the beam across the conductors is difiicult and can not be done unless the response of the individual conductor to the electron beam, as it is swept past the target row, is measured.

Kernkamp, for example, has flat, arrow-shaped conductors that are, at their smallest tips, 0.015 inch square. Assuming a spacing between conductors equal to the width of the conductor, this would mean only 33 conductors per lineal inch of image.

Kernkamp, as is common with most recorded references in the art, discloses no method of making these conductors extremely close together; for example 500 per lineal inch, nor does Kernkamp describe a method of focussing or aligning the beam trace with the row of conductors, other than distorting the electron beam from its normal circular cross section.

This problem is further made difficult because the interior ends of the conductors are not flush with the interior end face of the tube, but extend into the tube from the end wall. If a small diameter spot electron beam is used with a close conductor spacing, the diameter of the beam as it contacts each conductor the same size as the conductor itself; for example, 0.001 inch or smaller in diameter, a very small misalignment sometimes probits the tube from operating correctly because the beam does not properly contact the individual conductors.

The purpose of this invention is to overcome these difficulties and provide a novel method of construction of an electron emission control cathode ray tube, which permits an extremely close conductor spacing, with provision for visible view of the electron beam trace at all 'times, with simple alignment of the electron beam trace,

and to further provide a means to control the formation of two or more separate and distinct external images at the same time, and further to provide a means for supplying more than one cathode ray beam to each emission conductor at the same time, and further to provide a new and novel method of operation.

The cathode ray tube described in this invention can be used with a single electron gun or with a multiplicity of electron guns.

These and other objects will be seen from the following specification and claims in conjunction with the appended drawings in which:

FIG. 1 is a fragmentary, partially broken away, perspective view of one form of the present emission control tube.

FIG. 2A is a fragmentary plan view of the present tube.

FIGS. 2B, 2C, 2D and 2E are fragmentary sections on an increased scale, taken on line 2B2B of FIG. 2A showing slight variations in tube construction.

FIG. 3 is a schematic plan view of the present emission control tube as used for the simultaneous forming or printing of images.

FIG. 4A is a fragmentary perspective view of the present tube illustrating the use of a control field.

FIG. 4B is a fragmentary enlargement of a portion thereof.

FIG. 5 is a fragmentary section taken on line 55 of FIG. 3.

FIGS. 6A and 6B illustrate a pair of emission control tube end faces.

FIG. 7 is a fragmentary plan view of the present tube with means for supplying a bias potential to the emission conductors.

FIG. 8 is a partially sectioned diagrammatic view of an emission control tube employing an additional externally modulated high voltage source.

FIG. 9 is a similar view illustrating another method of operation.

FIG. 10 is an elevation view illustrating the initial step in the method of constructing the conductor strip of FIGS. 1 and 6A.

FIG. 11 is an end elevational view thereof.

FIG. 12 is a front elevational view of the completed conductor strip; and FIG. 13 is an end view thereof.

FIG. 14 is a diagrammatic elevational View of the present Image Control Tube, and certain electrical connections.

FIG. 15 is a right side elevation thereof showing its end wall.

FIG. 16 is a perspective view of one form of present tube.

FIG. 17 is a fragmentary elevational section of the end portion of the tube shown in FIG. 14 on increased scale.

It will be understood that the above drawings illustrate merely several preferred embodiments of the invention and that other embodiments are contemplated within the scope of the claims hereafter set forth:

In one simple envisioned embodiment of the invention, as in FIG. 1, and shown in cross section in FIG. 3, in a cathode ray tube 11' there are a plurality of electron guns and control elements, each containing an electron emission source 35, connected by lead 36 to power line 37, a beam forming electrode 35, a control grid 38, and accelerating anode 39; and internal or external beam focussing and deflection systems 3-4.

The multiplicity of electron emission and control guns are positioned at one end of a cathode ray tube, and a target plate of conductors 8 is positioned at the other end of the evacuated tube, with conductors 14 aflixed thereto and the assembly substantially perpendicular to the longitudinal axis of the tube. This plate is therefore substantially perpendicular to the direction of travel of the undeflected electron beams 11. Target plate 8 consists of a support plate of insulating material, such as glass, to which are affixed a series of coplanar closely spaced (such as 500 per inch), elongated conductors 14 in insulated position on said plate. This plate can also be the endface of the cathode ray tube, with the conductors on the interior surface, said conductors extending across the end face plate in such a manner that the ends of the conductors are external to the tube, while a substantial portion of their lengths are on the interior surface substantially perpendicular to the longitudinal axis of the tube.

These conductors can be formed in many ways. One, for illustration, shown in FIGS. 10, 11, 12 and 13 is to vacuum coat by evaporation, a glass plate 8 with a conducting material 21, such as gold, silver, platinum, copper, etc. Alternately a liquid solution of the metal may be painted on the glass strip and furnace fired. This conducting film is then coated with a photo-resist; the photosensitive surface thusly formed is exposed to a light-image of parallel lines and the non-light-hardened resist developed off. A suitable etching solution will remove the exposed portions of the conductor surface, and when the remaining resist is removed, a series of coplanar closely spaced elongated conductors 14 remain in insulated position on the glass plate. This etching process is well-known to those versed in the art.

An electro-fiuorescent material 55, FIG. 2E such as Willemite, for example, is coated on the glass surface between the conductors in such a manner that an electron beam striking the conductors and hence the fluorescent material, as the beam is deflected, will show a visible trace and permit focussing the beam to the smallest spot size, for good definition, and allow alignment of the trace so that it properly sweeps all of end face conductors 14.

The fluorescent layer may be coated over the entire interior of the tube end face plate 8, conductors 14 and insulating support as well.

This may be formed by the settlement process, or evaporation process, or any other of the methods Wellknown to those versed in the art. The fluorescent material can be athxed to the plate either before or after it is sealed to the body of the cathode ray tube.

Glass plate 8 with conductors 14 affixed is sealed into the tube as its end wall, or otherwise afiixed, by using a low-temperature melting point glass, such as Corning type 7570, which appears as the fillet 10 in FIGS. 2B, 2C, 2D and 2E.

To control the emission of secondary electrons which may be released from the target end face conductors 14 when they are struck by the electron beam 11, a series of wires, rods, or thin-edged plates can be affixed as shown in FIGS. 2A, 2B, 2C and 2D.

These conductors, which are positioned across end face conductors 14 and spaced therefrom, can be suitably connected in a circuit 56, FIG. 2E and FIG. 3 so that they reflect any secondary electrons emitted from the target end face conductors 14 back to the conductors themselves and inhibit their emission.

FIG. 2B shows parallel wires or rods 50 used for this control field. FIG. 2C shows thin-edged plates 52.

FIG. 2D shows thin wires or rods 50 and a sheathcathode 53 used as an emission source and connected into power circuit 57, FIG. 3.

FIG. 2B shows a coating 54 of high or low resistance conducting material such as stannous chloride or selenium, which is separated from end face conductors 14 by the insulating fluorescent material 55, and is used as a control field for the end face target conductors.

FIG. 2A shows the end face parallel field-wires 50.

FIGS. 23, 2C and 2D are cross sections of FIG. 2A, taken at 2B2B showing the interior conductive coatings 5 of copper, graphite, silver, platinum, etc. serving as a secondary anode. The end plate control field conductors are also shown in FIGS. 4A and 4B.

Insulating plate 8 with conductors l4 afiixed, substantially perpendicular to the longitudinal axis of the undeflected electron beam, can be of any shape, and is not limited to the standard endface shapes normally used in cathode ray tubes. For example, the end face can be circular, square, rectangular, triangular, polygonal, or even shaped like an O, or donut-shaped, with a circular hole in the center. Many other forms too numerous to list here can be used. Conductors affixed to this end plate do not necessarily have to be straight, or extend completely across the glass plate. Neither do they have to be parallel.

Depending on the number of external images desired, or other use to which an electron emission control tube can be put, the pattern of the conductors on the glass plate can take many forms. A pair of these are shown in FIGS. 6A and 6 B.

FIG. 6A is a rectangular glass plate 8 with a series of straight, parallel, coplanar closely spaced elongated conductors 14 afiixed in insulated position to said plate and arranged in a row, the respective ends of said conductors terminating at the respective edges of said glass plate.

It is substantially identical to the plate with conductors affixed as used in my invention, now Patent No. 2,771,336, and also described in my patent applications Nos. 607,446 and 623,152, above referred to.

These conductors can be bi-sected, as shown in FIG. 68, to give two parallel external-emission rows 70-71. This can be accomplished by forming the conductors in the manner described, but having the negative of the image of lines, to which the photo-resist is exposed, separated, and not continuous from edge to edge.

There are many advantages of operation of this design and type of electron emission control tube over the patents of record. One method, for example, using a single layer end face tube with parallel conductors substantially perpendicular to the axis of the undeflected electron beam, with end face conductors 14 as shown in FIGS. 1, 2A, 2B, 2C, 2D, 3, 4A, 4B, 5 or 6A, is shown in operation in FIGS. 1 and 3.

Several methods of operation, as described in my Patent No. 2,771,336, and patent application No. 623,152, are shown in FIG. 3.

Since an electron emission control tube of this type can form more than one image at once, two image control stations are shown.

In operation, external accelerating electrodes 32 and 32' are positioned as shown in FIG. 3, external to the tube surface and spaced therefrom, but parallel to the emission ends of the end face conductors 14.

The electron beam 11 is swept across the parallel conductors by a saw-tooth signal, for example, as described in my Patent No. 2,771,336 and US. Patent 2,934,673.

The methods of operation as described in my Patent No. 2,771,336 also apply to this tube, except that two complete separate and distinct images are simultaneously formed at two stations, as shown in FIG. 3. The two images thus formed do not have to be formed by the same method.

Briefly, the electron beam 11 is swept in contact with each conductor 14 in sequence, and modulated by an external signal 54 applied at 26 to the control grid 38 of the electron gun.

As the electrons in the beam contact each conductor 14, they are conducted transversely to the exterior of the tube, through the side wall, and escape the external ends of the conductors and travel through space, for eX- ample, 0.001 inch, in the direction of the external acceleration electrodes 32-32. This acceleration electrode may be a metallic knife-blade, or comb design, as is shown in references cited as patent issued and applications filed by myself, or can be parallel conductors 45 formed on an insulating glass plate 44, as shown in FIG. 1, and interconnected.

The exterior accelerating electrode is described in my Patent No. 2,771,336, and patent 2,934,673. It can be, for example (see FIG. 5 and FIG. 1) a series of parallel conductors 45 alfixed to a glass plate 44 or other insulating material, with the spacing the same as the spacing of the conductors 14 in the end face plate 8 of the electron emission control tube, with all of the conductors 45 connected at 118 at one edge of the plate and the unconnected ends of the conductors 45 parallel to and opposite the external emission ends of the tube end face conductors 14.

When the image control electron emission tube is used with a smoke-mist generator system as described in my Patent No. 2,771,336, and also shown in FIG. 3, the electrons travel through a smoke-mist pigment 36, to a movable image receiving web 28', which is positioned between the external electrode 32' and the conductor ends, and spaced for example, .002 inch from the external emission end of the tube conductors. Particles of pigment 36' are deposited on and in the image web in proportion to the image signal 54' applied to the electron gun modulating grid 38 of the cathode ray tube.

Other types of operation can consist, for example, of forming invisible electrostatic images on movable webs,

, past the end fact of the tube.

or rotating drums, with subsequent use, or said electrostatic image being remotely made visible, or transferred to another media, as described in the two aforementioned patents, or other processes well known to those versed in the art.

If the smoke-mist pigment generator 34', the housing 34, the blower 35", and the smoke-mist pigment 36' are removed, the operation is as follows:

When the tube is in operation, the high voltage electron (6005,000 volts, for illustration) beam 11 is caused to scan the row of conductors 14 by the deflection system, and by varying the intensity of the scanning field, the electron beam 11 will be so deflected as to intermittently scan the row of conductors 14 starting with conductor at extreme left in FIG. 4A, and ending with the conductor, for example, on extreme right.

The electron beam scans this row of conductors during a slow moving deflection field, and returns to the start of the scan during a rapid-retrace or fiyback signal in the conventional manner.

As shown in FIG. 3, the web 28 is adapted to move The image signal designated by the numeral 54' is fed to the control grid 38 of the electron gun assembly by the lead wire 26. The high voltage electron beam is emitted from the cathode in the quantity allowed by the instantaneous image signal on the control grid. The electron beam 11 passes through the scanning field and strikes one conductor 14, passes through the conductor and through the side of the tube, and then passes through a space, in the direction of the external accelerating electrode 32, inside the rotating drum 29', with the circuit completed through lead 33.

As the electron beam 11 passes to the web 28', an electr'ostatic charge is impressed thereon. Thus with the beam successively scanning the conductors 14 from one end to the other of the row, an electrostatic charge or image will be impressed on the web 28' in a row corresponding to the emission ends of the row of conductors 14. Thus as the web 28 of paper or plastic material or other material moves, electrostatic image lines will be formed across said web corresponding to the intensity of electrons passed by the control grid of the electron gun.

to the gun assembly through the lead 26 as shown in FIG. 3.

The high voltage electrode 32 can be operated at a higher potential than the accelerating anode 39. The instantaneous and varying potential of the grid 38 as regulated by the image signal 54 thus controls the deposition of an electrostatic charge or image upon the web 28' in a row corresponding to the emission end of the row of spaced conductors 14.

A complete description of this process will be found in my application S.N. 623,152.

For detailed operation of the tube with the smoke mist pigment system, refer to my Patent No. 2,771,336.

The other image forming station of FIG. 3 can be another process completely described in my application 623,152. At this station, for example, the electrostatic image is formed directly on a drum 59, and subsequently made visible by pigment at station 61, and transferred to the image web 28 extending around rolls 60-60 by the high voltage fields set up by high voltage discharge grid 63 and receiving anode 63.

Said image is subsequently fused to the Web at the station 62 and 62, and the drum cleaned by the rotating brush 65 and vacuum system 66.

Another method of operation is to constantly charge the drum with an evenly distributed electrostatic field with a high voltage charging apparatus at 64 and 64', and the emission from the conductors 14 counteracting this charge.

Another method of operation is to form an evenly distributed electrostatic charge on the surface of the drum 59 by the high voltage charging apparatus 64 and 64' with the electrons emitted from the emission ends of the conductors 14 which travel across space in the direction of the high voltage accelerating electrode 32, depending upon the image signal 54 fed to the electron gun that emits the beam 11, said electrons variously not affecting the charge, dissipating the charge partially, dissipating the charge completely, or dissipating the charge and being in such excess that they form a charge of the opposite polarity in varying amounts on the surface of the drum.

Thus, after the rotatable drum surface passes the emission ends of the conductors 14, the charge on the surface could be the original charge, no charge at all, or the opposite polarity charge, in varying amounts.

All of these image deposition systems are described in my Patent No. 2,771,336, application No. 623,152, or application No. 607,446.

Such systems include having the electrostatic charge formed on the web 28' being subsequently made visible at station 67 and made permanent at station 68, among other methods.

When used with a smoke-mist generator system, as described in Patent No. 2,771,336, briefly, the electrons travel through the smoke-mist pigment 36 to the movable image receiving web 28, which is positioned between the external electrode 32' and the emission ends of the conductors 14, and spaced from the external emission ends of the conductors.

Particles of pigment are deposited on and in the image Web in proportion to the image signal applied to the electron gun modulating grid 38 in the cathode ray tube.

Because of the length of each conductor 14 exposed to the interior of the tube, substantially perpendicular to the longitudinal axis of the tube, the electrons from more than one electron gun, FIG. 3, can be simultaneously swept past the row of end-face conductors without inter-action or interference, with the traces of each beam simultaneously visible. Multiple beams of electrons can be synchronized to strike the same conductor at the same time, or be out of harmony and synchronization and phase. Multiple electron beams can be used to supply multiple information to the conductors, or to increase the effective beam current without increasing electron beam spot size, by supplying the same information to each beam modulating control grid, when the beams are synchronized.

When a tube of this type is used to control an external smoke-mist pigment, or to form invisible electrostatic images, etc., as described in the three references cited, or in any other manner, the emitted electron beam, when it escapes the end of the conductors 14 and travels across space in the direction of an external accelerating electrode 32, must ionize the air or other gaseous media in the space, and bring the image web 28 or rotating drum surface 59 to ionization potential before an image is formed.

This is not the case in the tubes operated as in Kernkamp No. 2,291,476, or in Sabbah et al., No. 2,015,570, or in any of the other tube devices which were invented and designed to be operated in contact with another image receiving media, such as an electro-sensitive recording paper (Teledeltos paper), photographic film, etc. There, an electric circuit of low resistance is completed and the target conductors as in Kernkamp do not have to be designed as escape-points for electrons, nor must any appreciable ionization potential be built up before an image will be formed. But in an image control tube such as herein described where the electrons escape the ends of the conductors and travel through space in the direction of external acceleration electrodes 32-32, the potential impressed on the conductors 14 by the electron beam 11 must be high enough to ionize the (air) space and the image web, etc., before any electron emission will occur from the exterior ends of the end-face conductors, and hence form an image.

So all image-electrons which escape the external ends of the conductors must first be at the minimum ionization potential of the system (including the (air) space, image web or rotating drum surface, etc.), before any emission will occur.

For a gap in air of 0.001 inch and a good insulating paper as the image Web, this ionization potential may be in the order of 600-800 volts. One way to overcome this difiiculty is to pre-charge the individual conductor as it is swept by the image-signal electron beam, with such precharge or bias voltage at or just below the ionization potential of the system. Then, when the cathode ray electron beam contacts a conductor, electrons escape the exterior end of the conductor in direct response to the image signal applied to the modulating control grid of the image electron beam gun. This pre-charging of each conductor may be done in many ways. One is shown in FIG. 1, also in FIG. 5.

FIG. 1 is a cut-away view of the end face of an image control emission tube, and FIG. 5 is a cross section taken on line 55 of FIG. 3, which would also correspond to the perspective drawing shown in FIG. 1.

Two of the electron beams from the plurality of electron guns are shown striking the conductors. One is a small cross-section beam 11, and strikes only one endface conductor at a time as it is swept across the tube end face 8. The other beam 23 is of larger cross section, and may strike not only the conductor that is the target of the small-diameter beam, but one on each side of it. Now, the large diameter electron beam 23 is operated at a voltage such as 575 volts, for example, just below the described ionization potential of the space and Web system, so that the image-signal target conductor in sequence (and one on each side of it if desired) is raised to a potential just below the ionization potential of the image system (air gap, image web, etc.). The small diameter electron beam 11, which is the image signal beam, can then traverse the gap and web and form electrostatic images, or deposit smoke pigment, etc., depending on the method of operation, without first having to ionize the gap and web system, etc.

The large diameter beam 23 also provides a field to control secondary electrons which might be emitted when the small diameter electron beam 11 strikes the target conductors 14, and prevents them from collecting on the nearby conductors and surface of the glass or insulating end plate 8. This system also eliminates the image beam from having to charge up the target conductors to ionization potential before an image signal will bridge the space as it escapes the exterior end of each conductor.

Another method of pre-charging the end face conductors to slightly less than ionization potential is by positioning an electron emission source, other than a de fiected electron beam 11, so that the end face conductors are all charged to the same bias potential at once, but so that the conductors are not interconnected, and are still electrically insulated, so that an image signal fed to one conductor 14 by the small-diameter electron beam 11 will not be emitted by any conductor other than the instantaneous target conductor.

This can be done by positioning a cold cathode or hot cathode emission source 53 spaced from, but extending across all of the end face conductors, as shown in FIGS. 2D and 2E.

This electron emission source, although one unit, acts as though each external electron emission conductor is connected to the ionization potential by a diode, which permits electron flow in one direction only; no reverse flow is permitted. If this is a hot cathode emission source, suitable heater connections must be provided as is well known to those versed in the art. Connections to this emission source are not shown in this drawing, in order that it may be more clearly understood; such connections are well known to those versed in the art.

The emission source is shielded at 119 so that it is protected from the electron beam 11, and still permits emission to the end face conductors. type electron emission source.

Several parallel wires 50, parallel to each other and to the electron bias emission source, can be positioned parallel to and closely spaced from the end face and across but insulated from the conductors, as shown in FIGS. 2D and 2B, to provide a target field that will also discourage and control secondary electron emission, in the manner of screen-grids in vacuum tubes, as is Wellknown to those versed in the art.

These wires and electron emission source can be interconnected and at the same potential, or at difiFerent potentials.

Many types of circuit connections can be made to control this field.

The cathode ray beams 11 pass between the wires 50, as shown in FIGS. 2D and 2B.

The control field Wires 50 can'be kept at a potential more negative than the accelerating anode 39, for example, or varied from the bias potential of the conductors 14. If suitably connected, the control field wires can themselves be used as cold-cathode ionization bias emission sources. This is shown at in FIG. 2B. Here, the parallel wires 50'not only act as a controlfield but also as an electron emission bias source. These wires 50 are partially shown in FIG. 4A, but omitted from the drawing in FIG. 5 for clarity. The rotating drums 29 and 29' are also omitted from the drawing of FIG. 5 for clarity.

Because thin wires of substantial length, when connected in a high voltage field, tend to vibrate, the wires 50 of FIG. 28 can be replaced with thin edged strips 52, as in FIG. 2C, which can act as emitters 121 in the same manner.

In FIG. 2E, a metallic evaporated film 54 is shown insulated from the Wires 14 by the fluorescent material 55, but still providing a control field for the target conductors 14. This layer 54 may also be a semi-conductor, or a high resistance material, but it may not be an insulator.

FIG. 2A shows the wires 50 of FIG. 2B as they extend across the conductors 14.

Other types of electron emission sources can be used, internal or external to the tube.

A diode 121 or single-direction flow rectifier is inserted in the connection to the end face cathode emission source 53, in FIG. 3, to prevent a circuit from being completed from the electron gun to the beam, through the end face grid or emission source 53 back to the high voltage D.C. source 37.

In FIG. 3, the end face control grid 50 is connected to the cathode emission source 53, to simplify the diagram, but it is understood that they can be connected at separate points in the external circuit.

The two external accelerating electrodes 32-32 can be operated at different potentials, depending on the image systems used, pigments, etc., such as 1000 and 1100 volts, for illustration.

The fluorescent screen 55, FIG. 2E can be coated over conductors 14 and end face both, and a thin film 54 of conducting material such as aluminum, silver, etc., evaporated over it, to provide a continuous film to act in the same manner as the end face control field grid wires 50 already described in re: FIGS. 2A and 2B.

The conducting film 54 is only a few microns thick and is easily penetrated by the electron beam 11, while being insulated from the individual end face conductors 14 by the fluorescent layer 55. A suitable connection 56 to the film must be brought outside the tube for control and connection in the external circuit 37, FIG. 3, as is well known to those versed in the art.

The internal bias emission source can be formed on the end plate of the tube.

FIG. 7 shows an external bias pre-charge source 131 This is a sheath connected in unidirectional contact with one end of the emission conductors 14. In this instance, only the other ends of the conductors 14 can emit electrons.

In this case, a series of parallel wires 14' are formed on a glass plate 131 similar to FIG. 6A. A rectifying coating 132 is formed over them, such as selenium, copper oxide, etc., and this is then in contact with one end of the conductors 14.

This permits flow from the external source 131 to the conductors 14, but no flow from the electron beam 11 and conductors back to the external source or to another conductor.

There is a rectifying junction between the external source 131 and each individual conductor 14, which permits flow from the external bias source to the conductors 14, but not back to the external source.

Other forms of internal and external bias pre-charge sources can be used.

FIG. 8 illustrates a method of operation, where the cathode beam current is constant and the image signal supplied as an added force exterior to the tube. An image tube 134 is set up to form electrostatic images on a moving web 135, as has been described in my patents above pending. The modulating control grid of the electron beam 11 of the electron gun assembly 136 is adjusted to give a beam current and potential that will almost, but not quite, ionize the gap 137 between the tube face-plate conductors 14 and the image web 135. This potential scanning the tube end face conductors successively brings each conductor and the web opposite and the space between up to ionization potential, but no electrostatic image is formed.

An additional potential must be supplied to form the image. This can be done in many ways; one is shown in FIG. 8. An external control, such as a triode vacuum tube 138, is connected to the exterior ends of the cathoderay electron-emission control tube by a unilateral device,

such as a diode 139, rectifying junction etc., so that potential may flow from the external source 140, through the triode 138, through the rectifying junction 139, through the tube end face conductors 14 and escape their other ends, to bridge the ionized space 137 and form an electrostatic image on the moving web 135.

This external force is supplied to all conductors at the same time, but only the conductor being scanned by the constant-potential electron beam will permit current flow and/or an electrostatic image to be formed on web 135 because the other conductors and the space exterior to their ends and the image web opposite are not at the ionization potential. A current limiting resistance R may be added in this circuit, as can other electrical components such as the load resistor R to control this external force. A triode tube 138 is shown for clarity; a pentode, or other tube, or transistor, or modulating device can be used.

The external potential must be of greater value than the electron beam, in relation to the external accelerating electrode 32. In FIG. 8, the external force is a greater negative value. This tube can also be operated with the external force opposing a constant-value electron beam. In this instance, the external potential is controlled by the modulating signal to permit a constant, even charge pattern to be deposited on the moving web, etc. This emission is then interrupted by the force of potential controlled by the cathode ray beam system. In such an instance, the circuit connections as shown must be modified. In this way, a reverse of the original electrical image can be formed. Also, if the moving web 135 is given a constant pro-charge by a high-voltage emission device, such as a corona discharge field, as at 6363', FIG. 3, then the constant emission from the external potential source through the conductors can be adjusted to just counteract this precharge on the moving web.

Then when another potential, such as controlled by the cathode ray beam for example, neutralizes or partially neutralizes the effect of the potential from the external controlled source, part of the original pre-charge is permitted to remain on the image web, thereby forming an invisible electrostatic image. This same system can be used to deposit a smoke-mist pigment, etc., or form images in any of the other ways described in my patents or pending applications or in manner known to those versed in the art.

This method can also be used to put both positive and negative electrostatic charges on the same image web at the same time. The cathode-ray beam and external image or bias potential can counteract the precharge on the moving web and in addition supply the opposite charge, thereby, forming both positive and negative electrostatic images.

The external potential can also be used as a modulated source and the cathode ray beam as a modulated source, and with both being controlled, the instantaneous charge, either positive or negative, formed, is determined by the sum or the differences of the potential from the cathode ray beam emission tube and the external potential, etc.

In FIG. 8, the moving web is passed over the external accelerating electrode 32 directly; no rotating drum is used.

FIG. 9 shows another method for controlling this external potential. In this case, the accelerating electrode 32 is boosted to a higher potential by the action of the control triode 141, which receives the image signal, rather than the conductors in the end face of the control tube.

Many other ways of controlling this external signal potential are possible, as will be readily seen by those versed in the art.

When the external force is opposing the field set up by the cathode ray beam 11 and the external accelerating electrode 32, the triode 141 must be reversed and other circuit connections made, as will be readily seen by those versed in the art. A diode 142 is provided in FIG. 9 to prevent current flow from the accelerating potential connection to the accelerating electrode 32 through the triode 141 to the higher potential source.

In FIG. 8, the rectifying junction contacting the external ends of the conductors may be as described in FIG. 7, for example.

The circuits shown in FIGS. 8 and 9 may be operated with the external potential controlled by the triode for example supplying the ionization field for the gap and web system, and the image signal supplied by the modulated electron beam of the cathode ray emission control tube, if desired.

One advantage of the external triode-image-control system is that the triode or external modulating device can be designed to be operated at a higher frequency response than the cathode ray beam modulation system.

Only one tube end-face conductor 14 permits electron emission at any one time, because only one conductor has the combination of cathode ray and external potential, at any one instance, because the cathode ray beam is swept across the conductors, as previously described, and only contacts on at any instant.

Even though the other conductors may be at ionization potential, they can not form images. And also even though all conductors may be supplied the image signal by the external device, only one will be supplied the extra ionization bias necessary to permit emission across the space and to the image Web 135 before the signal is permitted to be formed thereon.

When a series of final electron emission conductors that are afi'ixed to an insulating supporting surface receive electrons from a series of cathode ray electron emission control tubes, the second modulated voltage, described as being applied to the electron emission conductors that are homogeneous to the heretofore described electron emission control tubes, can be applied through unilateral rectifying junctions for example, directly to the final emission conductors with the additional second modulated voltage supplying the bias precharge voltage of the system, or supplying the modulated image signal, or a combination of both, as already described.

The final electron emission conductors that are not homogeneous to the cathode ray tubes may emit electrons at points remote from the homogeneous emission conductors of the tube, but perform all of the functions inherent to the homogeneous emission conductors.

These final emission conductors must always be retained in insulated relation to each other but the emission ends of the final conductors do not have to be in the same spaced relation to each other as the portions of the conductors that receive electrons from the cathode ray tube emission conductors. This permits various designs of emission conductors corresponding to the heretofore described tube end plate designs, but the designs are of external final emission conductors aflixed to an external insulating support surface or surfaces, separate from the tube construction.

Herebelow is a description of FIGS. 1417 corresponding to FIGS. 1-4 of my copending application Serial No. 607, 446 filed August 31, 1956, now Patent No. 2,934,673, of which the present application is a continuation in part, and wherein the numerals are the same, except that numerals 8, 12, 44, 45, 44' have been changed respectively to 8', 12', 44', 45' and 44" to avoid repetition herein:

Referring to the drawing of the present application, the image control cathode ray tube includes a hollow evacuated glass envelope 1 which includes the cylindrical shank C and the outwardly flared end portion D. Shank C is closed at its end as in FIG. 16; whereas the enlarged portion D terminates in the upright end face 6 which is arranged in a plane at right angles to the longitudinal axis of the tube and is relatively thickened with respect to the other wall portions of the tube as shown in FIG. 17.

One end of shank C houses the standard electron gun and control grid assembly 2 at one end thereof. A sandwich 7 of glass plates and parallel electrical conductors 9 therebetween are housed within end face 6 in the manner hereafter described. Said conductors are so sealed within said end that the corresponding ends of said conductors terminate respectively at the inside and the outside of the said end face for conduction therethrough selectively of a controlled electron beam. Conductors 9 are arranged in parallel insulated relation to each other, lie in a single plane passing through the longitudinal axis of said tube and are parallel thereto.

A pair of electro-static deflection plates 3 are provided for controlling the horizontal deflection or trace of electron beam 11 shown in FIG. 14. A second pair of electrostatic plates 4 are shown for regulating vertical deflection of said electron beam. It is contemplated that a magnetic deflection system could be substituted, if desired.

An interior conductive coating of copper, graphite, silver, platinum or the like is arranged upon the interior of the walls of the tube towards its enlarged end, and serves as a second anode high-voltage acceleration source for the emitted electron beam 11, as it is standard practice in the art.

The electron gun assembly 2 includes the cathode ray emitting element which is connected by lead 36 to power line 37.

Said electron gun assembly also includes the forwardly arranged axially aligned control grid 38 and the two forwardly arranged axially aligned focusing and accelerating electrodes 39 and 40. The voltages of the control grid and the said anodes are progressively increased with respect to each other toward the enlarged end of the tube for controlling the velocity of electron beam 11 in a conventional manner.

Control grid 33 responds to image signals 41 through the lead 42 for regulating the quantity of electrons which make up the electron beam 11 at any instant. Deflection plates 4 are employed to maintain the electron beam 11 in a horizontal plane which passes through the row of 12 conductors 9 as in FIGS. 14 and 16. The deflection horizontally of said beam is controlled by plates 3.

It is the purpose of the present device to effect a horizontal deflection of the electron beam for intermittent and successive registry with the various conductors 9 arranged in the row as shown in FIG. 16.

In use there is provided closely adjacent the exterior of tube 1 a high-voltage stationary electrode blade 44' supported at 44", and having a thin electron receiving edge 45' arranged parallel to and opposite from the row of conductors 9 in the tube end face 6. Said blade is connected to the power source by the lead 46.

When the tube is operating, the high voltage electron beam 11 is caused to scan the row of conductors 9 by the scanning field produced by a suitable deflection means well-known in the art. By varying the intensity of the scanning field the electron beam 11 will be so deflected as to intermittently scan the row of conductors 9 starting from one end and moving across to the other end as in FIG. 16.

The horizontal scanning field is actuated by a standard saw-tooth signal with the electron beam moving from one end to the other of said row of conductors during the slow moving horizontal signal and returning to its beginning point during the rapid retract or flyback signal in the conventional manner.

High voltage electrode 44' is operated at a higher potential than the accelerating anode 40; which in turn is at a higher potential than anode 39; which latter operates at a higher voltage than emitter 35. Control grid 38 is operated at a lower potential than said emitter. The instantaneous and varying potential of control grid 38 is regulated or modulated by the image signal 41 thus controlling the instantaneous quantity of electron flow in beam 11.

The above described image control tube may be operated from a non-interlaced television type video signal, or may be operated from a simple mechanical scanner, such as shown and described in the above mentioned copending patent application Serial No, 271,579 (now US. Patent 2,771,336).

In the construction of the present tube, a slot of rectangular cross-section is cut in end face 6 or formed therein when the tube blank is made, and which extends substantially across the tube end face, as shown in FIGS. 15 and 16.

The conductor-sandwich is sealed into the tube end face by a low temperature fusing point glass, such as Corning type 7570, for example. These sealing fillets are shown at 10 in FIG. 17. The sandwich includes a pair of glass strips, 8' positioned and immovably retained on opposite sides of the row of electrical conductors 9.

Metal plates or screens of fine wire may be positioned at 12 above and below the conductor assembly 7, and as shown in FIG. 17, and are electrically connected to the interior conducting coating 5 which latter is suitably grounded, FIG. 14.

A strip of material which will fluoresce when struck by the electron beam is arranged upon end wall 6 as at 13. This is in the nature of a standard phosphor screen which will emit light for example, for focusing and centering electron beam 11. The center line of the row of conductors 9 is generally designated at 21' in FIG. 15.

To make this tube, the glass and conductor strip 7 is inserted in the slot in end face 6, and sealed with the fillets 10 above described, which is a low temperature fusing glass. The other parts of the tube such as the interior coating 5, the electron gun and grid assembly 2 and the evacuation are standard in the art. The conducting screens 12, FIG. 17, may be inserted before the strip 7 is sealed in place.

One method of operation of this tube in reproduction apparatus is to modulate the electron beam 11 which passes through the conductors 9 and tube end face 6 by instant, as more fully described hereinabove.

a standard grid control assembly 2 such as shown in FIG. 14. The control grid 38 in response to image signals 41, FIG. 14 through the lead 42 regulates the quantity of electrons which make up the electron beam 11 at any When using a control grid to modulate the electron beam, the beam is cut off intermittently, as in shutting a gate, to stop the electron flow at any particular time or to any particular conductor in the time path of the horizontal sweep across the conductor row 9. Referring to FIG. 14, image control lead 42 to the grid 38 is connected with the power source 37 by the lead 43.

The end face control field conductors 50 and 52, etc., can be fashioned as a long rod or plate with short extensions perpendicular to its length, like the teeth of a comb.

There must be as many extensions as there are conductors,

With the same spacing, and each extension is then an escape point for an emission to said conductors. In this way, there is no inter-action between conductors because of a continuous field.

One of the most important advantages of an electron emission control tube of this family of designs is that the emission conductors are in a precise predetermined spaced geometric location, instead of a random mosaic design arrangement as in Sabbah 2,015,570, and are easily manufactured.

A tube with an end-face as in FIG. 6A can be operated 'with a continuous circular trace, and when in contact with end face, but may be intermediate the tube end face wall and the electron gun assembly.

Having described my invention, reference should now be had to the following claims:

I claim:

1. In an image control cathode ray tube including an evacuated envelope having an elongated cylindrical shank closed at one end and an enlarged portion at its other end terminating in an end wall substantially at right angles to the shank axis, an electron gun assembly within the closed end of said shank consisting of an electron emitting element, beam forming and focusing elements which confine said beam to circular cross section, a beam current control grid, and an accelerating anode; the improvement consisting of an insulating plate, a series of coplanar closely spaced elongated conductors aflixed in insulated position to said plate and arranged in a row lying in a plane substantially at right angles to said axis,

the respective ends of said conductors terminating at the respective outer edges of said plate, portions of each conductor being exposed to the interior of the tube so that electrons impressed thereon by the electron beam from said gun assembly escape the exterior ends of said conductors to pass through space towards an external accelerating electrode, said beam being modulated by said gun assembly in response to an exterior signal transmitted thereto, and a deflection system intermediate the ends of said tube exteriorly energized to produce a continuously changing field, said beam being defiectable for transversely scanning said row of conductors throughout its length to provide transmission of electrons to the exterior of the tube, a rectifying coating on said conductors, and an external voltage unidirectionally connected therethrough to the said emission conductors, with said conductors retained in insulated relation from each other.

2. In an electron emission control tube including an evacuated envelope, an electron gun assembly, and beam forming and control elements; the improvement including an electron beam target assembly consisting of a substantially monoplanar electrically insulating support plate, a series of substantially monoplanar non-intersecting electrical conductors affixed in insulated position to said plate, said conductors terminating in ends adapted to receive and emit electrons, with the emission ends of said conductors terminating at the periphery of said plate on the exterior of said envelope, with a portion of said conductors exposed to the cathode ray electron beam, said portion being substantially perpendicular to the path of the undefiected electron beam, an external electron accelerating electrode spaced from and parallel to the emission ends of said conductors, and an electron emission source providing a bias voltage to each emission conductor, said emission conductors being retained in insulated relation to each other, with the bias voltage almost equal to the voltage necessary to raise the space between an emission conductor and said electrode to ionization potential.

3. In the control tube of claim 2, said bias voltage being variable so that the bias pre-charge on each emission conductor is retained at the value almost equal to the ionization potential of said space, and a movable surface of image receiving material interposed between said emission conductors and said electrode.

4. In the control tube of claim 2, said bias emission source being external to the cathode ray tube and connected to the individual emission conductors so that all emission conductors remain in insulated relation to each other.

5. In the control tube of claim 2, said bias source being located inside the cathode ray tube envelope and arranged so that all emission conductors remain in insulated relation to each other.

6. In an electron emission control tube including an evacuated envelope, an electron gun assembly, and beam forming and control elements; the improvement including an electron beam target assembly consisting of a substantially monoplanar electrically insulating support plate, a series of substantially monoplanar non-intersecting electrical conductors aflixed in insulated position to said plate, said conductors terminating in ends adapted to receive and emit electrons, with the emission ends of said conductors terminating at the periphery of said plate on the exterior of said envelope, with a portion of said conductors exposed to the cathode ray electron beam, said portion being substantially perpendicular to the path of the undeflected electron beam, said beam being modulated by said electron gun assembly in response to an exterior control signal transmitted thereto, said beam being defiectable for scanning individual conductors in said series to provide a selective transmission of electrons through said conductors to the exterior of said tube in the direction of an exterior accelerating electrode in response to said control signal, an additional second modulated voltage connected through a unilateral rectifying junction to each of said electron emission conductors, said additional voltage being modulated by a second control signal, with the second modulated voltage being in addition to the voltage impressed on the electron emission conductors by the internal cathode ray electron beam, with the second additional modulated voltage connected so that electrons, flowing from the second modulated voltage source to the individual electron emission conductors through the unilateral rectifying junctions, flow through said emission conductors in response to said second control signal and escape their external ends in the direction of an external electron accelerating electrode, with the sum of the second modulated voltage, plus the voltage impressed on the emission conductors by the interior cathode ray electron beam, equal to the sum of the bias pre-charge necessary to raise the space between an emission conductor and the external accelerating electrode to a level almost equal to the ionization potential of the said space plus the additional signal voltage necessary for a pre-determined quantity of electrons to be emitted from the exterior ends of said electron emission conductors in the direction of said external accelerating electrode, said quantity of electron emitted from said emission conductors being variable in response to the control signals and said electrons emitted from pre-selected emission conductors in response to a variable deflection field which determines which emission conductor is contacted by said electron beam, said selected conductor only emitting said electrons at any selected instant, and a receiving surface movably positioned between the emission ends of said conductors and said external electrode, with said electrons imposing an electrostatic charge on the receiving surface opposite therefrom, with the movement of said surface and the deflection and modulation of the cathode ray beam and the modulation of the additional second voltage electron source all synchronized to form electrostatic charges on the movable surface in a predetermined pattern.

7. In an electron emission control tube including an evacuated envelope, an electron gun assembly, and beam forming and control elements; the improvement including an electron beam target assembly consisting of a substantially monoplanar electrically insulating support plate, a series of substantially monoplanar non-intersecting electrical conductors affixed in insulated position to said plate, said conductors terminating in ends adapted to receive and emit electrons, with the emission ends of said conductors terminating at the periphery of said plate on the exterior of said envelope, with a portion of said conductors exposed to the cathode ray electron beam, said portion being substantially perpendicular to the path of the undeflected electron beam, said beam being modulated by said electron gun assembly in response to an exterior control signal transmitted thereto, said beam being deflectable for scanning individual conductors in said series to provide selective transmission of electrons through said conductors to the exterior of said tube in the direction of an exterior accelerating electrode spaced from and parallel to the emission ends of said conductors, an additional modulated voltage connected to the external accelerating electrode to variably increase the potential of the electrode in response to a second control signal, so that the sum of the additional modulated voltage connected to the electrode and the voltage impressed on the selected cathode ray tube electron emission conductor by the internal cathode ray electron beam is equal to the sum of the bias pre-charge voltage necessary to raise the space between the emission conductor and the acclerating electrode to a level almost equal to the ionization voltage of the space plus the additional signal voltage necessary for a predetermined quantity of electrons to be emitted from said selected emission conductor, in the direction of said external accelerating electrode.

8. In the control tube of claim 7, said quantity of electrons emitted from said selected emission conductors being variable in response to the control signals of the cathode ray tube electron gun and the second control signal of the additional modulated voltage, said control elements including a variable deflection field which determines which emission conductor is contacted by said electron beam, and a receiving surface movably positioned between the emission ends of said conductors and said external electrode, with the electrons emitted from said emission conductors in the direction of said electrode imposing an electrostatic charge on the receiving surface opposite therefrom, with the movement of said surface and the deflection and modulation of the cathode ray beam and the modulation of the additional second voltage electron source all synchronized to form electrostatic charges on the movable surface in a predetermined pattern.

9. A method of forming electrostatic images comprising movably positioning a receiving surface with a cathode ray electron emission control tube spaced from one side thereof, arranging an electron accelerating electrode upon the other side of the receiving surface, retaining the space between the electron emission conductors of said tube and said electrode at a bias voltage potential just below the ionization potential of said space, maintaining a bias voltage by a second emission source terminating at said emission conductors at one end of the circuit and said electrode at the other end of the circuit, and arranged so that all emission conductors are retained in insulated relation to each other, and additionally modulating a cathode ray beam electron emission source by a control signal, selectively deflecting said cathode ray beam to individual conductors, said modulated cathode ray beam voltage being in addition to the said bias voltage applied to the conductors, selectively deflecting said additional cathode ray beam electrons to individual conductors thereby determining which emission conductor permits electrons to escape its emission end in the direction of said electrode, controlling the quantity of electrons being emitted by a modulating signal, said emitted electrons imposing an electrostatic charge on the receiving surface opposite therefrom, with the movement of the receiving surface and the deflection and modulation of the selectively deflected and modulated electron beam all synchronized to form electrostatic charges on the movable surface in a predetermined pattern.

10. A method of forming electrostatic images comprising movably positioning a receiving surface with a cathode ray electron emission control tube spaced from one side thereof, arranging an electron accelerating electrode upon the other side of the receiving surface, selectively deflecting a uniformly constant voltage electron beam to pre-selected emission conductors of said tube thereby raising the space between said selected conductor, and said electrode to a bias voltage potential not quite equal in value to the ionization potential of said space, retaining the space between said conductors and said electrode at an instantly variable voltage level not exceeding the ionization potential of said space, maintaining said instantly variable voltage level by a second modulated voltage emission source terminating at said emission conductors at one end of the circuit and said electrode at the other end of the circuit, retaining said conductors in insulated relation to each other, modulating said separate second voltage by a control signal, said separate modulated voltage being at its maximum individually below the ionization potential of said space with all emission conductors at all times receiving said modulated second voltage, but only the selected emission conductor, to which the uniformly constant voltage electron beam is deflected, receiving the sum of the bias voltage potential plus the additional modulated second voltage from the separate voltage source, with said selected conductor receiving said sum of said voltages emitting electrons from its emission end in the direction of said electrode, controlling the qauntity of electrons being emitted by said modulating signal, said emitted electrons imposing an electrostatic charge on the receiving surface opposite, with the movement of the receiving surface and the selective deflection of the constant voltage electron beam and the modulation of the separate modulated voltage supplied to all conductors synchronized to form electrostatic charges on the movable surface in a pre-determined pattern.

11. A method of forming electrostatic images comprising movably positioning a receiving surface with a multiple electron gun cathode ray electron emission control tube spaced from one side thereof, arranging an electron accelerating electrode upon the other side of the receiving surface, selectively deflecting a uniformly constant voltage electron beam to pre-selected emission conductors of said tube thereby raising the space between said selected conductors and said electrode to a bias voltage potential not quite equal in value to the ionization potential of said space, modulating and deflecting a second electron beam in synchronization with said first uniform electron beam so that said second modulated electron beam is deflected to an emission conductor at the same time that the said emission conductor receives a bias voltage from said first constant value electron beam, said modulated electron beam voltage being in addition to the constant bias voltage electron beam, with the sum of the voltages raising the space between the selected conductor and electrode to ionization potential and permitting an emission of electrons from the conductor in the direction of said electrode, controlling the quantity of electrons being emitted by a modulating signal, said emitted electrons imposing an electrostatic charge on the receiving surface opposite, and synchronizing the movement of the receiving surface and the selective deflection of said electron beams and the modulated signal to form electrostatic charges on the movable surface in a predetermined pattern.

12. A method of forming electrostatic images comprising movably positioning a receiving surface with a cathode ray electron emission control tube closely spaced from one side thereof, said tube containing a series of electrically insulated electron emission conductors which receive electrons from a selectively deflected interior cathode ray emission source which is modulated by a control signal, transporting said received electrons to emission ends of said conductors exterior to the evacuated envelope of said cathode ray tube, arranging an electron accelerating electrode upon the other side of the receiving surface parallel to said emission ends of said conductors, connecting said electrode to accelerate electrons formed by the cathode ray beam electron emitting element of said cathode ray tube, and connecting a second modulated voltage through a unilateral rectifying junction to each of said emission conductors simultaneously retaining all electron emission conductors in insulated relation to each other, modulating said second source of voltage by a second modulating control signal, with said second voltage being in addition to the voltage impressed on said emission conductors by the internal cathode ray electron beam, connecting the second modulated voltage so that electrons flowing from the second modulated voltage source to the individual emission conductors through unilateral rectifying junctions, escape the exterior emission ends of said conductors in the direction of said electrode, controlling the quantity of electrons thus emitted by the second voltage modulating signal, with the sum of the second modulated voltage, plus the voltage impressed on the emission conductors by the interior cathode ray electron beam, equalling the sum of the bias pre-charge necessary to raise the space between the selected emission conductor and said electrode to a level almost equal to the ionization voltage of said space plus the additional signal voltage necessary to permit a predetermined desired quantity of electrons to be emitted from the emission end of said conductor in the direction of said electrode, controlling the quantity of electrons emitted by the modulating signals of the internal cathode ray electron beam and the second voltage, raising the space between all unselected emission conductors and the electrode to a level not exceeding the ionization potential of said space with said electrons emitted from said selected conductor imposing an electrostatic charge on the receiving surface opposite, and synchronizing the movement of said surface and the deflection and modulation of the selectivity deflected and modulated cathode ray beam and the modulation of the second voltage electron source to form electrostatic charges on the movable surface in a pre-determined pattern.

13. A method of forming electrostatic images comprising movably positioning a receiving surface with a cathode ray electron emission control tube closely spaced from one side thereof, said tube containing a series of electrically insulated electron emission conductors which receive electrons from a selectively deflected interior cathode ray emission source which is modulated. by a control signal, transporting said received electrons to emission ends of said conductors exterior to the evacuated envelope of said cathode ray tube, arranging an electron accereating electrode upon the other side of the receiving surface parallel to said emission ends of said conductors, connecting said electrode to accelerate electrons formed by the cathode ray beam electron emitting element of said cathode ray tube, and connecting a second modulated voltage to each of said emission conductors simultaneously, retaining all electron emission conductors in insulated relation to each other, modulating said second source of voltage by a second modulating control signal, with said second voltage being in addition to the voltage impressed on said emission conductors by the internal cathode ray electron beam, connecting the second modulated voltage so that electrons flowing from the second modulated voltage source to the individual emission conductors escape the exterior emission ends of said conductors in direction of said electrode, controlling the quantity of electrons thus emitted by the second voltage modulating signal, with the sum of the second modulated voltage, plus the voltage impressed on the emission conductors by the interior cathode ray electron beam, equalling the sum of the bias pre-charge necessary to raise the space between the selected emission conductor and the external electrode to a level almost equal to the ionization voltage of said space, plus the additional signal voltage necessary to permit a pre-determined desired quantity of electrons to be emitted from the emission end of said conductor in the direction of said electrode, controlling the quantity of electrons emitted by the modulating signals of the internal cathode ray electron beam and the second voltage, raising the space between all unselected emission conductors and the electrode to a level not exceeding the ionization potential of said space, with said electrons emitted from said selected conductor imposing an electrostatic charge on the receiving surface opposite, and synchronizing the movement of said surface and the deflection and modulation of the selectively deflected and modulated cathode ray beam and the modulation of the second voltage electron source to form electrostatic charges on the movable surface in a predetermined pattern.

References Cited by the Examiner UNITED STATES PATENTS 2,273,793 2/ 1942 Ekstrand 34674 2,291,476 7/1942 Kernkamp 1786.6 2,474,223 6/ 1949 Chevigny 315-21 2,896,112 7/1959 Allen et al 31521 2,900,443 8/1959 Camras 1786.6 2,933,556 4/1960 Barnes 1786.6 2,952,796 9/1960 Crews 31521 2,984,535 5/1961 Traite 34674 3,110,764 11/1963 Barry 178-6.6

DAVID G. REDINBAUGH, Primary Examiner.

RALPH G. NILSON, BERNARD KONICK, Examiners. 

1. IN AN IMAGE CONTROL CATHODE RAY TUBE INCLUDING AN EVACUATED ENVELOPE HAVING AN ELONGATED CYLINDRICAL SHANK CLOSED AT ONE END AND AN ENLARGED PORTION AT ITS OTHER END TERMINATING IN AN END WALL SUBSTANTIALLY AT RIGHT ANGLES TO THE SHANK AXIS, AN ELECTRON GUN ASSEMBLY WITHIN THE CLOSED END OF SAID SHANK CONSISTING OF AN ELECTRON EMITTING ELEMENT, BEAM FORMING AND FOCUSING ELEMENTS WHICH CONFINE SAID BEAM TO CIRCULAR CROSS SECTION, A BEAM CURRENT CONTROL GRID, AND AN ACCELERATING ANODE; THE IMPROVEMENT CONSISTING OF AN INSULATING PLATE, A SERIES OF COPLANAR CLOSELY SPACED ELONGATED CONDUCTORS AFFIXED IN INSULATED POSITION TO SAID PLATE AND ARRANGED IN A ROW LYING IN A PLANE SUBSTANTIALLY AT RIGHT ANGLES TO SAID AXIS, THE RESPECTIVE ENDS OF SAID CONDUCTORS TERMINATING AT THE RESPECTIVE OUTER EDGES OF SAID PLATE, PORTIONS OF EACH CONDUCTOR BEING EXPOSED TO THE INTERIOR OF THE TUBE SO THAT ELECTRONS IMPRESSED THEREON BY THE ELECTRON BEAM FROM SAID GUN ASSEMBLY ESCAPE THE EXTERIOR ENDS OF SAID CONDUCTORS TO PASS THROUGH SPACE TOWARDS AN EXTERNAL ACCELERATING ELECTRODE, SAID BEAM BEING MODULATED BY SAID GUN ASSEMBLY IN RESPONSE TO AN EXTERIOR SIGNAL TRANSMITTED THERETO, AND A DEFLECTION SYSTEM INTERMEDIATE THE ENDS OF SAID TUBE EXTERIORLY ENERGIZED TO PRODUCE A CONTINUOUSLY CHANGING FIELD, SAID BEAM DEFLECTABLE FOR TRANSVERSELY SCANNING SAID ROW OF CONDUCTORS THROUGHOUT ITS LENGTH TO PROVIDE TRANSMISSION OF ELECTRONS TO THE EXTERIOR OF THE TUBE, A RECTIFYING COATING ON SAID CONDUCTORS, AND AN EXTERNAL VOLTAGE UNIDIRECTIONALLY CONNECTED THERETHROUGH TO THE SAID EMISSION CONDUCTORS, WITH SAID CONDUCTORS RETAINED IN INSULATED RELATION FROM EACH OTHER.
 9. A METHOD OF FORMING ELECTROSTATIC IMAGES COMPRISING MOVABLY POSITIONING A RECEIVING SURFACE WITH A CATHODE RAY ELECTRON EMISSION CONTROL TUBE SPACED FROM ONE SIDE THEREOF, ARRANGING AN ELECTRON ACCELERATING ELECTRODE UPON THE OTHER SIDE OF THE RECEIVING SURFACE, RETAINING THE SPACE BETWEEN THE ELECTRON EMISSION CONDUCTORS OF SAID TUBE AND SAID ELECTRODE AT A BIAS VOLTAGE POTENTIAL JUST BELOW THE IONIZATION POTENTIAL OF SAID SPACE, MAINTAINING A BIAS VOLTAGE BY A SECOND EMISSION SOURCE TERMINATING AT SAID EMISSION CONDUCTORS AT ONE END OF THE CIRCUIT AND SAID ELECTRODE AT THE OTHER END OF THE CIRCUIT, AND ARRANGED SO THAT ALL EMISSION CONDUCTORS ARE RETAINED IN INSULATED RELATION TO EACH OTHER, AND ADDITIONALLY MODULATING A CATHODE RAY BEAM ELECTRON EMISSION SOURCE BY A CONTROL SIGNAL, SELECTIVELY DEFLECTING SAID CATHODE RAY BEAM TO INDIVIDUAL CONDUCTORS, SAID MODULATED CATHODE RAY BEAM VOLTAGE BEING IN ADDITION TO THE SAID BIAS VOLTAGE APPLIED TO THE CONDUCTORS, SELECTIVELY DEFLECTING SAID ADDITIONAL CATHODE RAY BEAM ELECTRONS TO INDIVIDUAL CONDUCTORS THEREBY DETERMINING WHICH EMISSION CONDUCTOR PERMITS ELECTRONS TO ESCAPE ITS EMISSION END IN THE DIRECTION OF SAID ELECTRODE, CONTROLLING THE QUANTITY OF ELECTRONS BEING EMITTED BY A MODULATING SIGNAL, SAID EMITTED ELECTRONS IMPOSING AN ELECTROSTATIC CHARGE ON THE RECEIVING SURFACE OPPOSITE THEREFROM, WITH THE MOVEMENT OF THE RECEIVING SURFACE AND THE DEFLECTION AND MODULATION OF THE SELECTIVELY DEFLECTED AND MODULATED ELECTRON BEAM ALL SYNCHRONIZED TO FORM ELECTROSTATIC CHARGES ON THE MOVABLE SURFACE IN A PREDETERMINED PATTERN. 